An optical fiber distribution frame is described in the document EP 0 886 158 which includes a first cross-connection panel and a second cross-connection panel facing each other. A first support is provided for connection modules belonging to each panel, each module on the first panel being adapted to be connected to one end of an optical fiber of a first group, each module on the second panel being adapted to be connected to one end of an optical fiber of a second group. An optical fiber of the first group is adapted to be connected to an optical fiber of the second group by a jumper fiber which has two ends respectively received in a port of one of the modules on the first panel and in a port of one of the modules on the second panel. During a cross-connection operation, the connection module support on which the jumper fiber to be cross-connected is located is positioned vertically so that, using an appropriate tool, an operative can insert said fiber into the mass of jumper fiber ends that are connected to the cross-connection panel containing said support or extract it therefrom. Because of the rotation of the connection module supports, the distribution frame described in the document EP 0 886 158 provides very easy access to the jumper fibers to be manipulated.
Although the density of the above distribution frame is advantageous, it also makes it difficult to insert a tool manually into the row of fibers connected to a support raised to the vertical position. There is a permanent risk of disturbance to adjacent fibers in the event of misoperations by the operative while working on the frame.
The drawback of the above distribution frame is eliminated in the frame disclosed in the document U.S. Pat. No. 5,784,515, which describes an optical fiber distribution frame in which the jumper fibers are cross-connected automatically. The distribution frame includes a horizontal cross-connection panel which includes a first series of holes into which adapters (connectors) for optically aligning the fibers are fixed. A first robot arm under the cross-connection panel connects or disconnects the fibers. The cross-connection panel further includes a second series of holes through which the surplus lengths of fiber pass. A second robot arm above the cross-connection panel handles the management of these surplus lengths in order to free space for the first robot arm to move around in it.
Although the above distribution frame has the advantage of being automatic, the use of two robot arms considerably complicates management of the fibers to be cross-connected. Furthermore, because the distribution frame must be equipped for its maximum potential capacity when it is first commissioned, this necessarily generates an installation overinvestment that is incompatible with progressive introduction of optical fibers into telecommunications networks.
The documents U.S. Pat. No. 5,436,987 and JP-A-07-333530 both describe high-capacity automated distribution frames which cross-connect jumper fibers at a single connection point. A robot connects or disconnects any fiber from an end selected from among a mass of fibers. An automatic winding system manages the surplus lengths of fiber. In U.S. Pat. No. 5,436,987, two rollers feed the fibers that are not in use to a stowage area. In JP-A-07-333530, an arm fitted with a hook picks up a jumper fiber that is not in use in order to stow it.
Although the distribution frames described in the above two documents can provide high capacities, management of the surplus lengths of fiber nevertheless remains difficult, the winding system being relatively complex.